1. Field of the Invention
The present invention is directed to a hydrodynamic coupling device, particularly a hydrodynamic torque converter, such as can be used, for example, in the drivetrain of a vehicle.
2. Description of the Related Art
Especially in drivetrains with internal combustion engines, a constant torque can generally not be introduced into a drivetrain because periodic ignitions occur in the internal combustion engines and the energy released as a result is converted into a rotational movement of the crankshaft. The torque delivered by the crankshaft and the rotational speed thereof are both subject to fluctuations and oscillations or, generally speaking, rotational irregularities. Because rotational irregularities of this type may be noticeable in driving mode, a general objective is to eliminate these rotational irregularities as far as possible.
For example, it is known in torque converters to use energy accumulators or energy storages, i.e., for example, springs or moving masses or combinations thereof, to temporarily store the energy occurring in rotational irregularities of the kind mentioned above and then to guide it into the drivetrain in such a way that a smoother speed characteristic or torque characteristic can be achieved. So-called turbine torsional vibration dampers and two-damper converters are examples of this. Mass pendulums known as speed-adaptive mass dampers convert the rotational irregularities occurring in driving condition into oscillating deflections of vibrating masses; the deflection is carried out in opposition to a centrifugal force and, by predefining the deflection path and the masses to be deflected, it is possible to tune to particular excitation speeds or excitation frequencies. Mass dampers of this type can, of course, be combined with systems of masses which execute oscillations through the use of springs or the like.
Because of the increasingly restricted space availability in modern vehicles, there is also less installation space available for the systems used for vibration damping with consequent loss of decoupling quality, i.e., in the reduction of occurring rotational irregularities.